#include<iostream>
using namespace std;

class Base{
    protected:
    static int num;
    public:
    static void sayHello(){
        cout<<"hello base;"<<num<<"\n";
    }
};
int Base::num = 0;
class Derived:public Base{
    public:
    void sayHello(){
        cout<<"hello derived class;"<<"\n";
    }
    int getBaseNum() {
        return Base :: num;
    }

};

int main() {
    Base b;
    Derived d;
    b.sayHello();
    d.sayHello();
    cout<<d.getBaseNum()<<endl;
    return 0;
}

